Robotic-assisted surgical systems have been developed to improve surgical precision and enable the implementation of new surgical procedures. For example, robotic systems have been developed to sense a surgeon's hand movements and translate them to scaled-down micro-movements and filter out unintentional tremors for precise microsurgical techniques in organ transplants, reconstructions, and minimally invasive surgeries. Other robotic systems are directed to telemanipulation of surgical tools such that the surgeon does not have to be present in the operating room, thereby facilitating remote surgery. Feedback-controlled robotic systems have also been developed to provide smoother manipulation of a surgical tool during a procedure than could be achieved by an unaided surgeon.
However, widespread acceptance of robotic systems by surgeons and hospitals is limited for a variety of reasons. Current systems are expensive to own and maintain. They often require extensive preoperative surgical planning prior to use, and they extend the required preparation time in the operating room. They are physically intrusive, possibly obscuring portions of a surgeons field of view and blocking certain areas around the operating table, such that a surgeon and/or surgical assistants are relegated to one side of the operating table. Current systems may also be non-intuitive or otherwise cumbersome to use, particularly for surgeons who have developed a special skill or “feel” for performing certain maneuvers during surgery and who find that such skill cannot be implemented using the robotic system. Finally, robotic surgical systems may be vulnerable to malfunction or operator error, despite safety interlocks and power backups.
Certain surgical procedures, such as neurosurgery, orthopedic surgery, and spinal surgery require precise movement of surgical instruments and placement of devices. For example, spinal surgeries often require precision drilling and placement of screws or other implements in relation to the spine, and there may be constrained access to the vertebrae during surgery that makes such maneuvers difficult. Catastrophic damage or death may result from improper drilling or maneuvering of the body during spinal surgery, due to the proximity of the spinal cord and arteries. Common spinal surgical procedures include a discectomy for removal of all or part of a disk, a foraminotomy for widening of the opening where nerve roots leave the spinal column, a laminectomy for removal of the lamina or bone spurs in the back, and spinal fusion for fusing of two vertebrae or vertebral segments together to eliminate pain caused by movement of the vertebrae.
Surgeries that involve screw placement require preparation of holes in bone (e.g., vertebral segments) prior to placement of the screws. Where such procedures are performed manually, in some implementations, a surgeon judges a drill trajectory for subsequent screw placement on the basis of pre-operative CT scans. Other manual methods which do not involve usage of the pre-operative CT scans, such as fluoroscopy, 3D fluoroscopy or natural landmark-based, may be used to determine the trajectory for preparing holes in bone prior to placement of the screws. In some implementations, the surgeon holds the drill in his hand while drilling, and fluoroscopic images are obtained to verify if the trajectory is correct. Some surgical techniques involve usage of different tools, such as a pedicle finder or K-wires. Such procedures rely strongly on the expertise of the surgeon, and there is significant variation in success rate among different surgeons. Screw misplacement is a common problem in such surgical procedures.
In some procedures, such as osteotomy, a portion of the vertebra is removed (e.g., a wedge is created) such that the alignment of the spine can be changed. However, correcting the shape of the spine manually is difficult, prone to error, and cumbersome. For example, FIGS. 2A through 2D illustrate the principles of osteotomy, which is to correct the shape of the spine. A part of the vertebra is removed in order to obtain the right curvature of the spine. After part of the vertebra is removed, the vertabra(e) is fixed with the screws as shown in FIG. 2D to prevent spinal instability. An example osteotomy instrument is shown in FIG. 3. A surgeon manipulates this instrument, sometimes by hitting it with a hammer, to remove part of the vertabra(e). Similar procedures can be performed on other portions of a patient's skeletal structure.
Inaccurate or incorrect surgical procedures such as osteotomies, are frequent and typically the result of inadequacy of instruments and the difficulty of accurately removing portions of the bone with manual tools. Thus, there is a need for a robotic surgical system to assist with surgical procedures.